[CVE-2026-68348][MODERATE REGULAR] ASoC: tas2781: bound firmware description string parsing [ Upstream

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-68348
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: tas2781: bound firmware description string parsing [ Upstream
Commit: 3ddb0d3e36507615e5ef010a879357a54870adf5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ddb0d3e36507615e5ef010a879357a54870adf5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68348
Analysis date: Mon, 10 Aug 2026 16:32:19 -0400
ActionableScore: 4
ActionableScore lower bound: 1
Actionable bucket: Borderline manual review recommended
Manual review required: YES

Summary:
The TAS2781 firmware parser used unbounded strlen() on firmware description strings before validating an in-blob NUL terminator, allowing a malformed local firmware image to trigger an out-of-bounds read and potential kernel crash, with limited confidentiality concern only in paranoid deployments where non-root components can influence firmware loading.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68348 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68348

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: MODERATE REGULAR
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-68348	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H';CWE-125;CWE-170;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.1';DESCR 'The TAS2781 firmware parser can call strlen() on variable length description strings before proving that a NUL terminator exists inside the firmware blob. A malformed firmware image can make the parser read past the end of the firmware buffer, which can cause an out of bounds read and potentially a kernel crash during firmware parsing. For the CVSS the PR:L is used in the paranoid score because some deployments may allow a reduced capability local service, container root, or firmware update helper to influence the firmware image or trigger driver reload without full host administration. The issue is not network reachable. Impact is at least local denial of service via kernel crash. A limited confidentiality impact is possible in the paranoid interpretation because the primitive is an out of bounds read, but no write primitive or direct privilege escalation path is evident from the code change.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended (with actual score 3)	YES	ERRORPATH HARDWARE  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=4
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 4
* Final recommended bucket: **Borderline manual review recommended**

## 2. Signal breakdown

Paranoid score signals:

* Firmware-mediated external influence: +1
  The malformed input is a firmware blob parsed by the TAS2781 codec driver.

* Local unprivileged trigger: +1
  Not true in default conservative deployments, but plausible in some environments where a reduced-privilege firmware update helper, container root, or service account can influence firmware content or trigger driver reload.

* Reliable kernel crash / strong DoS: +1
  Unbounded `strlen()` can walk beyond the firmware buffer and fault in kernel context.

* Confidentiality impact plausible: +1
  The primitive is an out-of-bounds read. No direct disclosure path is shown, so this is only a paranoid limited-confidentiality concern.

* Privileged kernel/device-management memory corruption path: +1
  Firmware-fed parsing occurs inside a trusted kernel codec driver path.

* Rare AND difficult-to-reach subsystem/configuration: -1
  TAS2781 firmware parsing is device-specific and not a broad default attack surface.

Conservative score signals:

* Firmware-mediated external influence: +1
* Reliable kernel crash / strong DoS: +1
* Requires admin/root in typical deployments: -2
* Rare/device-specific path: -1
* Privileged firmware-fed driver path: +1

Net conservative result: 1.

## 3. Reachability analysis

Typical triggering requires supplying or replacing the TAS2781 firmware image and causing the driver to parse it. In normal deployments, firmware files are root-controlled under `/lib/firmware`, so the conservative interpretation treats this as local privileged.

A more paranoid interpretation is reasonable if firmware can be influenced by a vendor updater, reduced-capability service, container root with delegated device access, initramfs/update pipeline, or another local actor that is not full host root. The path is not network reachable. It is also not a broad kernel interface because it depends on TAS2781 hardware and the corresponding ASoC codec firmware parser.

Call-site confidence: medium-high. The vulnerable parsing sites are visible, but full firmware loading policy and product-specific update paths are not included.

## 4. Severity interpretation

This behaves more like an ordinary Moderate issue in default systems, but it is a borderline actionable Moderate for products where firmware update or firmware selection is delegated to less trusted local components.

The concrete primitive is an out-of-bounds read caused by unbounded `strlen()` before confirming an in-blob NUL terminator. This supports crash/DoS and limited confidentiality concern in a paranoid interpretation. It does not show OOB write, UAF, type confusion, arbitrary write, callback control, or a plausible direct privilege escalation path.

## 5. One-sentence report phrase

The TAS2781 firmware parser used unbounded strlen() on firmware description strings before validating an in-blob NUL terminator, allowing a malformed local firmware image to trigger an out-of-bounds read and potential kernel crash, with limited confidentiality concern only in paranoid deployments where non-root components can influence firmware loading.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review is recommended because this is a kernel out-of-bounds read in a firmware-fed parser, and product-specific firmware update paths may reduce the effective privilege requirement. It is not an Important candidate by default because there is no write primitive, UAF, object lifetime issue, or demonstrated privilege escalation path.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: ASoC: tas2781: bound firmware description string parsing [ Upstream
Commit: 3ddb0d3e36507615e5ef010a879357a54870adf5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ddb0d3e36507615e5ef010a879357a54870adf5

Changed files:
  sound/soc/codecs/tas2781-fmwlib.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ddb0d3e36507615e5ef010a879357a54870adf5

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DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-68348 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68348

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 6.1

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 1
  Paranoid ActionableScore: 4

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).